With Bloody Bills help I changed the FX1 file and uploaded it with Andy's Musket sounds. This isnt the same sounds we tried using before that sounded like popcorn. This one (as you can hear in the video) sounds awesome. Its not too loud but much louder than the other sound file we tried. Also sounds much, much better than musket sounds we use now.
So go into this file C:\Program Files (x86)\Steam\steamapps\common\napoleon total war\data
and take out NTW3_Fx1_v2.pack (just to be safe why dont you put this file somewhere on the desktop).
Go here and download
http://www.mediafire.com/?w5kdsu4dbjrkqeyAfter the download is finished extract to your data folder C:\Program Files (x86)\Steam\steamapps\common\napoleon total war\data (or you can extract to your desktop and manually place this in the data folder (location shown above).
And Walla...new awesome musket sounds. Ive tested everything and its fine.